Background: Although infectious diseases are less common in high-income countries compared to low-income countries, they should still be seriously considered as a relevant public health issue. Some professions, such as healthcare workers, laboratory workers, and care providers may be at a particularly high risk of acquiring infections. In Germany, work-related infectious diseases are after skin diseases, the most common cause of occupational diseases reported to the Institution for Statutory Social Accident Insurance and Prevention in the Health Care and Welfare Services (BGW). An occupational disease, as defined by the WHO, is “any disease contracted primarily as a result of an exposure to risk factors arising from work activity”, although this definition varies between countries. In order for infections to be recognized as an occupational disease, either the identification of an index case is needed or it must be shown that the likelihood in which a particular case of illness was attributable to the occupation: the probability of causation must be greater than 50% (the “more-likely-than-not” rule). A general “rule-of-thumb” is to equate the probability of causation of 50% with a relative risk of disease equal to two (the “doubling of the risk”). This principle is used by many countries for the recognition of an occupational disease. Few studies have concentrated on the risk of infectious disease in daycare workers, who may be at higher risk than the general population due to their frequent and close contact to young children.
Research questions: The primary aim of this review was to summarize the evidence on the relationship between being a daycare worker working with children and the possible increased risk for infections not preventable by vaccines. Furthermore, research gaps were to be identified. Finally, the implications for practice and health policy based on the evidence were to be described.
Methods: For the systematic reviews with meta-analysis, the Medline and Embase databases were searched using search strings defined according to the Population, Exposure, Comparison, and Outcomes (PECO) applicable to the research questions in order to find studies on vaccine non-preventable infections in daycare workers published since 2000. The search hits were evaluated using predefined inclusion and exclusion criteria by two independent reviewers. A separate manual search was performed by reviewing the reference lists of key articles and systematic reviews. The “citation tracking factor” by Google scholar was used to find additional relevant studies. The resulting studies were extracted and were assessed in eight risk of bias domains for the judgement of study quality. With a meta-analysis, the pooled risk of infections for daycare workers compared to the general or a reference population was calculated. The quality of evidence was assessed by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).
Results: After evaluating the 6879 records, ten methodologically adequate studies were identified regarding parvovirus B19 infection (four studies) and cytomegalovirus (CMV) infection (six studies). No adequate studies on other infections were found. For parvovirus B19 infection, three cross-sectional studies and one retrospective cohort study were identified. The pooled parvovirus B19 seroprevalence in daycare workers was 70.3% (95% CI 59.5-80.4). Of three studies investigating the relative risk (RR) of parvovirus B19 infection on daycare workers, only one study evaluated seroconversion rates. There was an indication for an increased risk of parvovirus B19 infection for daycare workers compared to the unexposed population (RR = 1.12, 95% CI 0.98–1.27) using prevalence estimators. Furthermore, daycare workers had a higher parvovirus B19 seroconversion rate compared to the unexposed population (RR = 2.63, 95% CI 1.27–5.45) in the low risk of bias study. For CMV infection, five cross-sectional studies and one cohort study were included. The pooled CMV seroprevalence of daycare workers was 59.3% (95% CI 47.6-70.9). The four studies investigating risk of infection indicated an increased seroprevalence for daycare workers compared to a reference population (prevalence ratio, RR=1.54, 95% CI 1.33-1.77). No study evaluated CMV seroconversions for daycare workers.
Conclusions: The findings suggest higher parvovirus B19 and cytomegalovirus seroprevalence for daycare workers compared to the general population. There is a need for longitudinal and higher-quality studies regarding infections not preventable by vaccines in daycare workers, as well as a need to study other infections for which daycare workers may be at higher risk. Nonetheless, when the actual occupational seroconversion risk is considered by taking into account the pre-occupational seroprevalences, the pooled relative risks for both parvovirus B19 and CMV infection are compatible with a doubled seroconversion risk corresponding to a probability of causation due to the occupation of at least 50%. Preventative efforts in the workplace are needed based on the legally required risk assessment at the workplace. Moreover, it is important to raise awareness of the potential risk of infection in women trying to conceive or during pregnancy. Recommendations to prevent infections in the day care center include using gloves and frequent handwashing after exposure to young children’s bodily fluids, cleaning surfaces, and avoiding intimate contact with young children if pregnant, although these measures alone may not completely protect the daycare worker from infection. Currently, in Germany, an employment ban for pregnant daycare workers depends on the federal state. To avoid occupational risks for pregnant daycare workers, scientific-based guidelines should be developed and applied consistently.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:70669 |
| Date | 29 April 2020 |
| Creators | Romero de Starke, Karla |
| Contributors | Seidler, Andreas, Garthus-Niegel, Susan, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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